FUEL SYSTEM

Question 1

How is Center Wing Tank Fuel scavenged?

Answer 1

CWT fuel is scavenged by 4 jet pumps pumping into main tanks 2 and 3
- Scavenge begins when main tank 2 or 3 fuel quantity decreases
to approximately 27,200 kgs

FCOM 2; 12.20.2

Question 2

Which cross feed valves are controlled by Fuel System Management logic
when setting T/O flaps?

Answer 2

•Crossfeed valves 2 and 3

FCOM 2; 12.20.13

Question 3

During the Before Start Procedure, at what center wing tank quantity are you
required to select the center wing pumps on? Quantity in lbs for the LCF?

Answer 3

•7,700 kgs or more in center wing tank
•17,000 lbs or more in center wing tank

FCOM 2; 12.20.13, LCF 12.20.8

Question 4

Main tank 2 and 3 override/jettison pumps can operate to a standpipe
level of approximately __ kgs (400), __ (LCF) and __ kgs (-8) of
fuel remaining in each tank?

Answer 4

•3,200 kgs
•7000 lbs
•3450 kgs

FCOM 2; 12.20.2, LCF 12.20.1, -8 12.20.2

Question 5

Describe how the fuel quantity indication changes upon termination of fuel jettison?

Answer 5

•The fuel to remain quantity indication changes from magenta to white.
•The fuel to remain quantity flashes for 5 seconds.

FCOM 2; 12.20.17

Question 6

How does Center Wing Tank Fuel scavenge in 400/-8?

Answer 6

•CWT fuel is scavenged by 4 jet pumps pumping into main tanks 2 and 3
NB: Scavenge begins when main tank 2 or 3 fuel quantity decreases to
approximately 27,200 kgs

FCOM 2; 12.20.2

Question 7

How does Center Wing Tank Fuel scavenge in the LCF?

Answer 7

•CWT electric pump into M2 tank when,
- CWT override/jettison pump has low pressure
- Fuel quantity in M2 or M3 tank is below 40200 lbs
NB: Pump will operate for approximately two hours or until
scavenge pump pressure is low, whichever occurs first.

FCOM 2; LCF 12.20.1

Question 8

State what occurs when you select the fuel jettison switch to A or B.

Answer 8

•Arms the jettison selector.
•Displays preselected fuel to remain on EICAS

FCOM 2; 12.10.4

Question 9

What is the impact on the aircraft with excessive fuel imbalance?

Answer 9

•Adversely affects CG
•Aerodynamic drag
•Fuel economy

FCOM 2; 12.20.3

Question 10

When do the FSMCs open the reserve transfer valves on the 400, LCF, -8?

Answer 10

•400: When main tank 2 or 3 fuel quantity decreases to approximately 18,200kgs.
(Fuel transfers from reserve tanks 2 and 3 to the related main tank.)
•LCF: When main tank 2 or 3 fuel quantity decreases to approximately 40,200 lbs.
(Fuel transfers from reserve tanks 2 and 3 to the related main tank.)
•-8: When main tank 1 or 4 fuel quantity decreases to approximately 6100kgs
(Fuel transfers from reserve tanks 1 and 4 to the related main tank.)

FCOM 2; 12.20.12, LCF 12.20.7, -8 12.20.8

Question 11

Inwhich tank is fuel temperature measured?

Answer 11

• Main tank 1

FCOM 2; 12.20.1

Question 12

In general, how would you handle an excessive fuel imbalance situation?

Answer 12

By opening or closing cross feed valves and turning off and on fuel pump switches.
(refer to QRH and Supplementary Procedures)

FCOM 1; SP.12.1& QRH 12.4

Question 13

Which fuel tanks do reserve tank 1 and 4 transfer to on the 747-8?

Answer 13

•Main tanks 1 and 4

FCOM 2 747-8; 12.20.8

Question 14

On the 747-8, at what fuel quantity will the fuel jettison complete jettison
operations with the selector in MLW position?

Answer 14

•Maximum landing weight plus 3000 kgs

FCOM 2 747-8; 12.20.11

Question 15

During fuel jettison on the LCF, transfer valves open when fuel quantity
in tanks 2 or 3 decrease to __ pounds?

Answer 15

•20,000 pounds

FCOM 2 747-LCF; 12.20.7